In recent years, a type of mobile communications network known as an “ad-hoc” network has been developed. In this type of network, each mobile node is capable of operating as a base station or router for the other mobile nodes, thus eliminating the need for a fixed infrastructure of base stations. As can be appreciated by one skilled in the art, network nodes transmit and receive data packet communications in a multiplexed format, such as time-division multiple access (TDMA) format, code-division multiple access (CDMA) format, or frequency-division multiple access (FDMA) format. More sophisticated ad-hoc networks are also being developed which, in addition to enabling mobile nodes to communicate with each other as in a conventional ad-hoc network, further enable the mobile nodes to access a fixed network and thus communicate with other mobile nodes, such as those on the public switched telephone network (PSTN), and on other networks such as the Internet. Details of these advanced types of ad-hoc networks are described in U.S. Pat. No. 7,072,650 entitled “Ad Hoc Peer-to-Peer Mobile Radio Access System Interfaced to the PSTN and Cellular Networks”, issued Jul. 4, 2006, in U.S. Pat. No. 6,807,165 entitled “Time Division Protocol for an Ad-Hoc, Peer-to-Peer Radio Network Having Coordinating Channel Access to Shared Parallel Data Channels with Separate Reservation Channel”, and in U.S. Pat. No. 6,873,839 entitled “Prioritized-Routing for an Ad-Hoc, Peer-to-Peer, Mobile Radio Access System”, the entire content of each being incorporated herein by reference.
As can be appreciated by one skilled in the art, it would be desirable for these types of networks to be able to employ different types of radios. This can be achieved by providing an abstraction of the physical layer of the nodes in the wireless network. Abstracting the physical layer of a node that routes packets in a wireless network is beneficial because it makes it possible to run the same software on different types of radio without having to make costly adjustments every time new radios of a different type are added to the network. The abstracted physical layer also makes it possible to replace the physical/media access control (PHY/MAC) layers of a wireless network without having to upgrade the networking layer as well, and enables multiple PHY/MAC layers to operate in a wireless network concurrently in order to increase capacity, compatibility or functionality of the network. In addition, the abstract physical layer makes it possible to upgrade a wireless network by adding PHY/MAC elements while maintaining backwards-compatibility, thus ensuring a smooth transition while terminal nodes are being replaced, and also enables a heterogeneous network of nodes to operate using a variety of PHY/MAC elements. For example, a long-distance, fixed infrastructure backhaul using directional antennas would provide a certain type of connectivity using high data rate, low mobility radios while a short-distance, low data rate nodes would provide extended coverage to mobile nodes.
Accordingly, a need exists for a routing protocol in a wireless communication network, in particular, a wireless mobile ad-hoc peer-to-peer communication network, that can enable operation of multiple heterogeneous radios at the same time.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.